The technical sector of the present invention is that of the systems for supplying and/or distributing screen-wash liquid for motor vehicles. Such a system accompanies a vehicle window wiping installation. More particularly, the invention targets a device for transporting and heating the liquid conveyed between a tank and a spraying system.
Motor vehicles are routinely equipped with wiping installations and washing systems to ensure the wiping and washing of the windscreen, and thus prevent the driver's vision of his or her environment being disrupted. These wiping installations comprise arms describing an angular reciprocal movement at the end of which are installed elongate brushes, which in turn bear scraper blades made of an elastic material. These blades rub against the windscreen and dispel the water by bringing it outside the field of vision of the driver. The brush is attached to the rotating arm of the windscreen wiper by an assembly consisting of a mechanical connector and an adapter. The connector is a part which is fixed directly onto the structure of the brush, the adapter being an intermediate part which makes it possible to fasten the connector, and consequently the brush, onto the arm of the windscreen wiper. These two parts are linked to one another by a transversal axis which allows their relative rotation.
The washing systems comprise a device for feeding a screen-wash liquid which is routed from a tank located in the vehicle and which is sprayed towards the windscreen by nozzles generally located on the bonnet, on the windscreen bay grating or on the windscreen wiper itself for a better distribution of the liquid. In the case of nozzles placed on the brushes, the screen-wash liquid is routed, before being distributed between them, by pipelines which are fixed onto the arms of the windscreen wiper and which are connected to a distribution system of the brush at the connector. The connector thus comprises orifices suitable for receiving, by a leak-tight link, the endpieces of said pipelines.
When the temperature of the screen-wash liquid is too low, for example below 5° C., the screen-wash liquid is heated to de-ice it or keep it de-iced. For this, a transport duct reheats the screen-wash liquid taken from a tank by a pump at the time when the screen wash control is actuated, generally by the control lever placed alongside the steering wheel and controlling, among other things, the actuation of the windscreen wipers.
The heating of the liquid in the transport duct is ensured by a heating element which runs next to the duct. It has also been proposed to incorporate this heating element inside the duct but such an incorporation poses problems of positioning of the heating element relative to the duct in which the liquid circulates, which is reflected in a degradation of the liquid heating function and a reduction of its efficiency over the length of the heating element. Furthermore, the arrangement of the heating element is not managed satisfactorily since overheating has been detected in certain areas of the heating element. It will be understood from the above that liquid transport and heating device as described above presents drawbacks.